AIF Sales Order Serivce create DocuRefHeader for attachment

Here is the scenario

Customer sends a sales order XML which we transform to AX XML representation of the sales order and drop to AIF. As a part of the AIF process, the customer sends reference to attachments which we pick up and would like to place in the AX document management folder. I would like to modify the inbound AX Sales Order document to include a docuRefHeader node of type attachment (or file) that points to the location of the attachment.

All the documentation I have read indicates only docureffHeader of type Notes can be created on sales order insert/update etc…

Is there a way around this? What are the recommended steps?

I suppose I could fabricate a note to treat it like a reference to a folder location. But I think it would be good for users to see the attachments using native attachment tools in whatever AX module that can have attachments.

AX 2012 R2 CU1 if anyone needs to know

Also, I have found that the SalesSalesOrderService only returns 1 DocuRefHeader node of type Notes on the read/find operations even though there are multiples. Curious where I would fix that limitation.